The space available for seating passengers in the passenger cabin of a commercial aircraft is limited. In times of increasing operating costs and in the intent to reduce the ecological impact of aircraft, there is a demand to increase the number of passengers that can be accommodated in an aircraft. One option to increase the amount of space available for seating passengers is the introduction of a so-called lower deck catering system. A lower deck catering system comprises a cargo unit arranged in a cargo hold, i.e. the lower deck of the aircraft, and a transport arrangement for transporting objects out of the cargo unit to a main deck of the aircraft and back from the main deck of the aircraft to the cargo unit. The cargo unit is used to store food or other goods, for example, goods for duty free shopping, for the passengers. Hence, the space which is currently occupied by the storage racks for food can be used to accommodate additional passengers.
Such a lower deck catering system does not only increase the space available in the passenger cabin of the aircraft, it may also be used to reduce the time that is required to unload waste and equip an aircraft with new objects between consecutive flights. To this end it has been suggested to disconnect a cargo unit from a transport arrangement permanently arranged in the aircraft after a flight and unload the disconnected cargo unit from the aircraft. Thereby, any remaining objects, such as unused food items and waste stored in the cargo unit can be quickly removed from the aircraft. Afterwards, another cargo unit or replenished cargo unit comprising new or fresh objects is loaded into the cargo bay of the aircraft and connected to the transport arrangement. Hence, instead of unloading and loading individual trolleys one by one, all trolleys can be loaded and unloaded from the aircraft in a single cargo unit.
The cargo units used in this approach require a transport opening in a housing of the cargo unit through which the transport arrangement can remove objects from a storage rack arrangement in the cargo unit and place objects in the storage rack arrangement. The transport opening has to be securely closed as long as the cargo unit is not connected to a transport arrangement in an aircraft. In particular, it has to be prevented that the interior of the cargo unit is contaminated or that items are illegally placed in the interior of the cargo unit, while the cargo unit is waiting on an apron to be loaded into the aircraft or while the cargo unit is transported from a catering facility to an airport.